A pseudorabies virus (PRV) is a porcine herpesvirus type I in a Varicella virus of hepersviridae alpha-hepersririnae subfamily, capable of leading to serious porcine diseases. The PRV frequently outbreaks epidemically, seriously endangers pregnant swine in particular, and often results in fetal death, abortion and fetal mummies. Replacement gilts and non-pregnant sows infected with the PRV may be subjected to infertility, failure to observe oestrus, return to estrus and repeat breeder syndrome. Infected boars show such symptoms as testicular swelling, atrophy and loss of ability to inseminate. Mass mortality of newborn piglets infected with the PRV may be caused, in which the death rate of newborn piglets aged within 15 days may reach up to 100%, and the death rate of newborn piglets aged 3-4 weeks may reach up to 30-40%. Each of fattening swine infected with the PRV develops a fever, respiratory symptoms and growth retardation, resulting in affecting weight gain and reducing feed conversion. Meanwhile, pigs are natural host for the PRV and a source of infection to it. It may have a great significance to control the porcine pseudorabies on not only a pig industry, but also the smooth development of the culture of other animals. Vaccine immunization is a radical measure for the prevention, control and elimination of the PRV. A majority of PRV vaccines currently sold on the market are live vaccines having differential diagnosis capabilities, including a vaccine product of naturally attenuated strain Bartha-K61 developed in Hungaria, a PRV live vaccine (SA215 strain) developed by professor Guo Wanzhu at Sichuan Agricultural University, and a PRV live vaccine (HB98 strain) developed by professor Chen Huanchun at Huazhong Agricultural University. Those vaccines that have been put on the market for use for many years play an important role in prevention and control of the porcine pseudorabies. There are some reports on virus isolation occasionally, but the porcine pseudorabies has been effectively controlled in general.
However, since 2011, suspected PR has occurred epidemically on a number of large-scale pig farms in which gene deleted live vaccines are used for immunity. PR mainly shows such symptoms that swinery gE antibody positive rate is significantly increased, sows produce weak piglets and dead fetuses, and the piglets may be subjected to neural symptoms, death and the like. In particular, the piglets aged 2-3 days may be subjected to serious PR, with the time from onset to death for 5 hours only. Currently, the PR has spread to a number of provinces and regions in China, has killed a lot of piglets, and has made great economic losses.
Therefore, in the present invention, an epidemic (prevalent) strain is isolated clinically and is determined as porcine pseudorabies virus (PRV)-YF strain through a gene sequence analysis and an immune protection test; and BEI inactivation is performed after the propagation; an inactivated vaccine is prepared and the immune efficacy thereof is evaluated.